Desmid
of the month
June 2003

Actinotaenium
didymocarpum

Actinotaenium
didymocarpum * is a rare, poorly known
desmid. In the Netherlands it was reported for the first time in summer
2002. Sampled from a small, shallow, mesotrophic dune pool, in the
first instance only vegetative cells were encountered. Originally,
those cells — on account of their minute median constriction and the
presence of asteroid chloroplasts — were labeled Actinotaenium
diplosporum var. americanum forma minus. However,
on the basis of the characteristically shaped twin zygospores that
were encountered later in the season it was concluded that the algal
material in question fully agreed with Actinotaeniumdidymocarpum as described from Lapland **.